Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint, idempotentHint, openWorldHint and destructiveHint=false, so the safety profile is covered. The description adds genuinely new operational context: it is free, requires no API key, and data is CC0 — relevant for auth and licensing decisions. It also enumerates returned fields, which is helpful though partly redundant with the output schema.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Two dense sentences that front-load the resource and access model before the mode and return details. No wasted clauses, though the trailing field enumeration is slightly redundant given an output schema exists.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Covers identity, access conditions, both call modes, and expected fields for a zero-required-param lookup tool. Since an output schema exists, the return-value listing is a bonus rather than a necessity, and nothing an agent needs to invoke it correctly appears to be missing.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100% and all three parameters are documented there, including LEI precedence over legalName and the limit default/max. The description restates the two lookup modes but adds no syntax, format, or constraint detail beyond the schema, so the baseline 3 applies.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb and resource ('Look up Legal Entity Identifier (LEI) records from GLEIF') and explicitly covers both operating modes: name search and exact LEI fetch. An agent can distinguish this from sibling entity tools like sec_edgar_company or companies_house_company without opening any schema.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Provides purpose context ('Use to identify legal entities and ownership/issuer identifiers across jurisdictions') which implies when it's relevant, but names no alternatives or exclusions despite many sibling tools covering entity/company data. Usage is suggested rather than routed.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.